Cerebral Cortex Advance Access published online on November 6, 2007
Cerebral Cortex, doi:10.1093/cercor/bhm190
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Effects of Visual Experience on Vascular Endothelial Growth Factor Expression during the Postnatal Development of the Rat Visual Cortex
1 Laboratory of Clinical and Experimental Neuroscience (LaNCE), Department of Neuroscience, Faculty of Medicine and Odontology, Basque Country University, Barrio Sarriena, 48940 Leioa, Spain, 2 Institute of Neuroscience CNR, via G. Moruzzi 1, 56100 Pisa, Italy, 3 Laboratory of Clinical and Experimental Neuroscience (LaNCE), Department of Nursing I, Basque Country University, Barrio Sarriena, 48940 Leioa, Spain
Address correspondence to Harkaitz Bengoetxea, PhD Department of Neuroscience, Faculty of Medicine and Odontology, Basque Country University, Leioa 48940, Bizkaia, Spain. Email: hbengoetxea{at}gmail.com.
The development of the cortical vascular network depends on functional maturation. External inputs are an essential requirement in the modeling of the visual cortex, mainly during the critical period, when the functional and structural properties of visual cortical neurons are particularly susceptible to alterations. Vascular endothelial growth factor (VEGF) is the major angiogenic factor, a key signal in the induction of vessel growth. Our study focused on the role of visual stimuli on the development of the vascular pattern correlated with VEGF levels. Vascular density and the expression of VEGF were examined in the primary visual cortex of rats reared under different visual environments (dark rearing, dark-rearing in conditions of enriched environment, enriched environment, and laboratory standard conditions) during postnatal development (before, during, and after the critical period). Our results show a restricted VEGF cellular expression to astroglial cells. Quantitative differences appeared during the critical period: higher vascular density and VEGF protein levels were found in the enriched environment group; both dark-reared groups showed lower vascular density and VEGF levels, which means that enriched environment without the physical exercise component does not exert effects in dark-reared rats.
Key Words: angiogenesis critical period dark-rearing enriched environment vascularization